Low thermal conductivity frame member, especially for windows, doors, facades and the like

ABSTRACT

A composite frame or profile member for windows, doors, facades and the like, has low thermal conductivity between the region separated by the frame member and has two spaced apart profiles connected by conductivity-limiting webs which have cleats engaged in grooves of the structural shapes. The webs are bridged by two or more ribs which can be perpendicular to the webs or inclined to them and the sum of the rib and web thicknesses when the ribs are perpendicular to the web should be not less than 3.8 mm, and when the ribs are inclined to the webs should be not less than 1.6 mm.

FIELD OF THE INVENTION

[0001] My present invention relates to a frame member of low thermalconductivity, serving as a heat-transfer-limiting member, especially forwindows, doors, facades and the like. More particularly, the inventionrelates to a heat-transfer-limiting composite member, which may bereferred to as a profile, and which is comprised itself of twostructural shapes or profiles which preferably are composed of metal,bridged by two thermal conductivity-limiting ribs which space thestructural shapes apart.

BACKGROUND OF THE INVENTION

[0002] Frame members of low thermal conductivity are provided in a greatvariety of shapes and configurations and serve as members of low thermalconductivity in frames for windows, doors, facades and the like whichare to have insulating capability, i.e. are capable of blocking the flowof heat from one side to the other of the window, door or other memberprovided with the frame. The panel or panels of the window or door, e.g.a double-pane window, are thermally insulated between two zones and byutilizing frame members or profiles of low thermal conductivity tosupport the panel or panels, the heat flow across the structural elementcan be greatly limited.

[0003] One of the more common constructions of such composite framemembers has a pair of structural shapes or metal profiles which can beextruded from aluminum or some other light metal or light metal alloyand which can be held apart by the aforementioned conductivity-limitingwebs. These webs, in turn, may be formed at their edges engageable withthe structural shapes, with formations that mate with and engage incomplementary formations of the structural shape. In a typicalconstruction of this type, the formations on the webs are cleats orbeads which are engageable in grooves of the structural shapes andpreferably have dovetail cross sections.

[0004] While such composite frame members are effective in providingstructural support in door, windows, facades and the like and have lowthermal conductivity, at least in part because of the low conductivitycross sections of the webs, it is desirable to further improve thethermal properties of such members, i.e. to reduce the heat flowthereacross still further.

[0005] While theoretically such further reduction in heat flow could bereduced by reducing the thicknesses of the webs, there is a limit to theextent to which the thicknesses can be reduced without loss ofmechanical and structural strength.

OBJECTS OF THE INVENTION

[0006] It is, therefore, the principal object of the present inventionto provide a frame member or composite profile of low thermalconductivity, i.e. thermal barrier properties, whereby drawbacks ofearlier systems are avoided and whose thermal and mechanical propertiesare optimized.

[0007] Another object of this invention is to provide an improvedcomposite profile for windows, doors, facades and the like which is freefrom the drawbacks of earlier composite profiles for these purposes.

SUMMARY OF THE INVENTION

[0008] These objects and others which will become apparent hereinafterare attained, in accordance with the invention, in a frame member of lowthermal conductivity for use as described and which comprises:

[0009] two spaced apart mutually parallel structural shapes each havinga pair of connecting formations along sides of the structural shapesfacing one another;

[0010] a pair of mutually spaced conductivity limiting webs each formedalong respective opposite edges with a connecting formation mating witha respective one of the connecting formations of a respective one of thestructural shapes whereby the conductivity limiting webs bridge betweenand interconnect the structural shapes, the webs being of substantiallyuniform thickness between the connecting formations thereof; and

[0011] a plurality of substantially planar ribs of substantially uniformthickness interconnecting the webs between the connecting formationsthereof and running substantially perpendicular to the webs or at aninclination thereto, a sum of the wall thicknesses of the webs and allof the ribs being no less than 3.8 mm where the ribs are perpendicularto the webs and no less than 1.6 mm where the ribs are inclined to thewebs.

[0012] When I refer to ribs which are inclined to the webs, I intend toso describe ribs which may not intersect or cross and are so inclined aswell as crossing pairs of ribs.

[0013] The advantages of the frame member of the invention reside in thecombination of thin wall webs which have low thermal conductivity withconnecting ribs which provide good mechanical properties with respect tocompressive strength, tensile strength, transverse torsional strength,shear stress resistance and rigidity, as well as other strengthparameters, together with good heat-blocking characteristics.

[0014] Advantageously the wall thicknesses of the individualconductivity-limiting webs is in a range between 0.5 and 1.5 mm, andmore preferably between 0.6 and 1.0 mm. The wall thicknesses of theindividual webs can also be between 0.8 and 2.0 mm. Best results areobtained with frame members which have two such ribs and each of theribs has a wall thickness between 0.8 and 2.0 mm and preferably between1.0 and 1.5 mm. A particularly effective combination of parameters inthe case of the thickness of the individual webs can also be between 0.8and 2.0 mm.

[0015] In the case of frame members with three such ribs, each of theribs can have a wall thickness between 0.3 and 2.0 mm and preferablybetween 0.8 and 1.5 mm.

[0016] The ribs can run perpendicularly to the webs or can be inclined,e.g. can cross. According to another feature of the invention a spacingbetween each of the formations of a respective one of said webs and arib proximal thereto is 20 to 40% of a spacing between structural shapesand preferably 25 to 30% thereof. Furthermore, it has been found to beadvantageous in the case of inclined ribs to have them adjoin the websat transverse segments connected to the respective formations or cleatsof the ribs.

BRIEF DESCRIPTION OF THE DRAWING

[0017] The above and other objects, features, and advantages will becomemore readily apparent from the following description, reference beingmade to the accompanying drawing in which:

[0018]FIG. 1 is a cross sectional view through a composite profileaccording to the invention illustrating a first embodiment;

[0019]FIG. 2 is a view similar to FIG. 1 of a second embodiment;

[0020]FIG. 3 is a view similar to FIG. 1 of a third embodiment; and

[0021]FIG. 4 is a view similar to FIG. 1 of a fourth embodiment.

SPECIFIC DESCRIPTION

[0022] The frame member or composite profile shown in the drawing can beutilized for windows, doors, facades and wherever structural strength isrequired in a frame but transmission of heat between opposite sides ofthe frame is to be suppressed. A composite profile according to theinvention can comprise two preferably metallic structural shapes orprofiles 1, 2 which are interconnected by individualconductivity-limiting webs 3 which hold the structural shapes 1 and 2apart and connect the profile into a structurally strong member. Thestructural shapes 1 and 2 have dovetail cross section grooves orformations in which dovetail cross section cleats 4 of the webs 3formfittingly engage. These cleats are located along the longitudinaledges of the webs 3.

[0023] To provide structural strength while limiting thermalconductivity, the webs are bridged by a plurality of connecting ribs 5.In the embodiment shown in FIG. 1, the ribs 5 are planar and lieperpendicular to the webs 3.

[0024] In FIG. 3, the webs 5 cross while in the embodiment of FIG. 4,the webs 5 cross, i.e. are inclined to one another but engage the webs 3at the transverse segments 8 which adjoin the cleats 4.

[0025] In the embodiment of FIG. 2, three such ribs 5 are providedperpendicular to the webs 3.

[0026] It has been found to be important, for the purposes of theinvention, that the sum of the thicknesses S1 of both webs 3 and S2 ofthe two or three ribs 5 which are at right angles to the webs 3 be aminimum of 3.8 mm, a value defined as the minimum wall thickness.

[0027] The maximum wall thickness sum can be 10 mm and preferably isaround 6 mm.

[0028] The wall thicknesses of the webs 3 should be between 0.5 and 1.5mm each, preferably between 0.6 and 1 mm. The wall thicknesses of theribs 5 in the embodiment of FIG. 1 should be between 0.8 and 2.0 mm andpreferably between 1 and 1.5 mm.

[0029] For the three rib embodiment of FIG. 2, the wall thicknesses ofthe connecting ribs 5 should be between 0.3 and 2.0 mm and preferablybetween 0.8 and 1.5 mm.

[0030] The distance 6 between one of the connecting ribs 5 and therespective dovetail 4 should be 20% to 40% of the total distance 7between the structural shapes 1 and 2 and preferably 25% to 35% thereof.The distance 7 between the structural shapes 1 and 2 can be between 20and 100 mm and the separation of the webs 3 midway between thestructural shapes 1 and 2 can be between 10 and 100 mm. When the ribs 5are inclined to the webs 3, the sum mentioned above should not be lessthan 1.6 mm.

I claim:
 1. A frame member of low thermal conductivity comprising: twospaced apart mutually parallel structural shapes each having a pair ofconnecting formations along sides of said structural shapes facing oneanother; a pair of mutually spaced conductivity limiting webs eachformed along respective opposite edges with a connecting formationmating with a respective one of the connecting formations of arespective one of said structural shapes whereby said conductivitylimiting webs bridge between and interconnect said structural shapes,said webs being of substantially uniform thickness between theconnecting formations thereof; and a plurality of substantially planarribs of substantially uniform thickness interconnecting said websbetween the connecting formations thereof and running substantiallyperpendicular to said webs or at an inclination thereto, a sum of thewall thicknesses of said webs and all of said ribs being no less than3.8 mm where said ribs are perpendicular to said webs and no less than1.6 mm where said ribs are inclined to said webs.
 2. The frame memberdefined in claim 1 wherein the wall thickness of each of said webs isbetween 0.5 and 1.5 mm.
 3. The frame member defined in claim 2 whereinthe wall thickness of each of said webs is between 0.6 and 1.0 mm. 4.The frame member defined in claim 1 which comprises two of said ribs andeach of said ribs has a wall thickness between 0.8 and 2.0 mm.
 5. Theframe member defined in claim 4 wherein each of said ribs has a wallthickness between 1.0 and 1.5 mm.
 6. The frame member defined in claim 1which comprises three of said ribs and each of said ribs has a wallthickness between 0.3 and 2.0 mm.
 7. The frame member defined in claim 6wherein each of said ribs has a wall thickness between 0.8 and 1.5 mm.8. The frame member defined in claim 1 wherein said ribs areperpendicular to said webs.
 9. The frame member defined in claim 1wherein said ribs extend in a cruciform pattern between said webs. 10.The frame member defined in claim 1 wherein a spacing between each ofsaid formations of a respective one of said webs and a rib proximalthereto is 20% to 40% of a spacing between said structural shapes. 11.The frame member defined in claim 10 wherein the spacing between each ofsaid formations of a respective one of said webs and a rib proximalthereto is 25% to 35% of the spacing between said structural shapes. 12.The frame member defined in claim 1 wherein said ribs are connected tosaid webs at transverse segments connected to the respective formationsof said ribs.
 13. The frame member defined in claim 1 wherein saidstructural shapes are composed of metal, said formations of said websare cleats received in grooves of said structural shapes and said sumhas a maximum of 10 mm.
 14. The frame member defined in claim 13 whereinsaid cleats and said grooves are of dovetail cross section and said sumhas a maximum of 6 mm.
 15. The frame member defined in claim 14 whereinthe wall thickness of each of said webs is between 0.6 and 1.0 mm. 16.The frame member defined in claim 15 which comprises two of said ribsand each of said ribs has a wall thickness between 1.0 and 1.5 nm. 17.The frame member defined in claim 15 which comprises three of said ribsand each of said ribs has a wall thickness between 0.8 and 1.5 mm. 18.The frame member defined in claim 17 wherein said ribs are perpendicularto said webs.
 19. The frame member defined in claim 17 wherein said ribsextend in a cruciform pattern between said webs.
 20. The frame memberdefined in claim 17 wherein a spacing between each of said formations ofa respective one of FEIGN said webs and a rib proximal thereto is 25% to35% of the spacing between said structural shapes.